The current article by Hong et al1 is another chapter in a long-running comprehensive study of oral health in children in Iowa. It describes a provocative finding of the possible association between fluorosis of permanent teeth and amoxicillin use in early childhood. In an earlier article, they noted a relationship between amoxicillin use and enamel defects on second primary molars, which prompted them to look at permanent teeth forming at about the same time.2 This research team has already identified changes in the diet of middle-class infants that have important implications for oral health, and the team has told us much about caries and primary tooth defects as a result of its long-running work with these children, so this finding deserves our attention.3,4 This most recent association between a poorly understood, difficult-to-treat dental abnormality and a commonly used pediatric medication holds implications for both dental and medical practice if it holds up to further study.